Hi everyone,

As the title said, ive recently noticed a cold start rattle that sounds almost like engine knock or wornout bearings. The sound is most apparent when the cold start ends (around 15-20 sec after start up) across 1-3k rpm but its loudest on deceleration. It does this until the engine temperature is to its normal operating temperature but I can still hear a faint noise when Im close to a wall. I only have 3300km on it, and havent done the first service yet. Do you guys think this is normal? Thank you

 

heres a link to a video I recorded the sound

 

Ohh. I was just about to post that it’s normal but ...Mine makes a similar noise sometimes on cold starts for like 0.5 second as oil pressure builds, when the car sits for awhile -- that is why it’s slightly concerning that yours is making that exact same noise after running for awhile. I thought it might be an issue on mine but all 3 of my friends P400’s make the noise when I hear them start them up, so I have stopped worrying about it.

Your noise is not normal.

Could be a number of things -- belt driven accessory noise (pulleys do go bad and make weird noises), could also be timing chain, valve clearance related (ie hydraulic lifter not getting oil it needs to pressurize -- which is to be honest what it sounds like), even a weird resonance of a component like an exhaust rattle or heat shield.v

The problem is, I have no reference point for what the above noises would sound like on the p400 motor. I could diagnose from sound on other LR motors, but not this one yet. I will say it does not sound like an exhaust rattle or heat shield to me.

You’re definitely under warranty with a 2024 - yes? Take it in and don’t accept it back until that noise is gone. I would not call this a good noise and I would be concerned as well.

 

thanks for the your insight. I took the car to the dealership and to no surprise they said it’s fine. I tested their demo car and had a similar noise. To their defense, when I recorded the video I was surrounded by the walls so the sound did amplify a bit more. Anyways, they told me to continue monitor and bring the car back if the noise increases over time. For now they cannot find anything wrong with it. My friend just got a P400 also so I’ll try listening to his.

When you said your car and friends does the same noise, is it after the rpm from cold start drops down? Thanks

 

I would immediately perform an oil change and see what this does.

 

This is a good idea. As long as I dont find any metal glitter/flakes I should be good right

 

@lilenday@gmail.com Does this sound repeat when accelerating? First and second gear around 1400RPM?

 

on acceleration I Cant hear it. But faintly when the rpm drops on deceleration I hear it. This is with windows down driving close to a wall, if it was wide open road I wouldn’t hear it at all. But it is within that 1400-2000rpm range for sure

 

Have you checked the error codes for engine misfire?

 

Hey @lilenday@gmail.com another member and I ( @jaredmonez@gmail.com ) have been dealing with this issue offline. He just had some amazing recent success with a tech that went above and beyond to get the the root cause of his rattle issue. Turns out there was oil leaking from his PCV tube into the intake! After weeks at the dealer, the car is home now and he is happy.
This could very well be your issue (as it could be mine as well) and gives you a baseline for a tech to take a look and hopefully remedy your issue. Good luck!